Despite the fact that numerous highway accidents result in situations in which a sleeping driver is out of control of his vehicle, no device which awakens a sleeping driver of a vehicle in motion is available today. Various devices for awakening sleeping drivers in such situations have been described in patent literature. Such devices are impractical, cumbersome to wear and hence may not be worn, or mechanically unreliable. For example: U.S. Pat. No. 4,209,075 (Messina) employs a spring attached to the seat belt. When the driver slumps forward, the tension on the seat belt is sufficient to increase the tension on the spring which is in turn controls various components of the vehicle.
U.S. Pat. No. 5,691,693 (Kithil). This invention employs at least three capacitive sensors, placed in the headliner of the vehicle and above the operator's head which senses changes in position and motion. The output of the sensors are analyzed by a micro processor which in turn activates various warning devices to alert the operator.
U.S. Pat. No. 5,689,241 (Clarke, Sr. et al.) This invention consists of a unit placed around the rearview mirror or the dashboard and contains an infrared auto focusing device to sense changes in position of the head. In addition, the unit contains a heat sensor which evaluates the temperature around the face area. This assumes a decrease in temperature about the face resulting from a decrease in respiration which occurs during sleep.
U.S. Pat. No. 5,682,144 (Mannik) This device attaches to the driver's eyeglasses. A beam of narrow band infrared or ultrasound senses whether the driver's eyelids are in a closed or open position.
U.S. Pat. No. 4,953,111 issued on 1990 (Yamamoto and Tanaka). This device detects the blink rate of the driver's eyes regardless of the position of the iris and uses at least two reflection type sensors. The duration of the blink is then used to determine whether the user is beginning to doze. An alarm is then produced to awaken the driver.
U.S. Pat. No. 5,469,143 November 1995 (Cooper). This device consists of eye glasses which contain a sensing lever in contact with one of the driver's upper eyelids. Downward motion of the eyelid moves the sensing lever downward which in turn activates a micro switch coupled to the sensing lever. The micro switch activates circuitry in the control unit to turn on a light each time the eyelid closes.
U.S. Pat. No. 5,684,461 November 1997 (Jones). This consists of a U-shaped headset which includes a mercury switch assembly. The mercury switch is closed with a forward tilting of the head. The unit, however, does require a headset.
U.S. Pat. No. 5,522,092 June 1996 (Streb, et. al.) This consists of a head cap operating a number of micro switches which detect forward and backward motion of the head. With tilting of the head switches then activate an alarm.
U.S. Pat. No. 5,353,013 October 1994 (Estrada). This device consists of a headset with a reflector mounted on the top. An incident optical beam is directed from a forward positioned light source. The optical emitter and receiver system is arranged so that the head position is sensed by displacement of the beam which in turn activates the alarm system to emit a loud alarm. This also requires a headset.
U.S. Pat. No. 5,195,606 March 1993 (Martyniuk). This is a switch activated by a piston cylinder which in turn activates the brake pedal or vacuum operated brake system.
U.S. Pat. No. 4,928,090 May 1990 (Yoshimi, et. al.) This device measures the skin potential for determining arousal level. It does so by a complex measurement of skin potential level which varies with sleep.
U.S. Pat. No. 4,489,375 November 1984 (Hershberger) This consists of a push button alarm switch mounted on the steering wheel whereby the driver's hand concurrently grips the steering wheel and switch. The alarm switch is activated when the driver's grip on the steering wheel is relaxed or in sleep.
U.S. Pat. No. 4,259,665 March 1981 (Manning). The device measures the electrical conduction between the driver's hand and the steering wheel. With relaxation of grip, the hand falls from the steering wheel and the safety system is activated.
U.S. Pat. No. 3,964,045 June 1976 (Conley). This invention requires the driver to wear a glove which is in turn connected to a switch. With sleep and relaxation the gloved hand falls from the steering wheel increasing tension on the cord which is connected to the switch. At this point the alarm is activated.
U.S. Pat. No. 5,559,495 September 1995 (Cochran). A sleep preventing alarm including timer circuitry for selectively transmitting a periodic indicator signal upon completion of a characteristic time interval in one of a number of modes of operation.